In total, 120 ‘Cheonghcheong/Nagdong’ doubled haploid (CNDH) populations was developed by F1 derived from a crossing whitebacked planthopper (WBPH, Sogatella furcifera) resistance ‘Cheongcheong’ and susceptible ‘Nagdong’ lines. The main objective of this research was to determine the rice resistance optimum screening after infesting by WBPH and identify quantitative trait loci (QTLs) associated with rice resistance in order to provide consistent information for marker-assisted selection (MAS) and develop new varieties. The genetic map with average 9.6 centimorgans (cM) between markers was constructed from 120 CNDH populations using 217 SSR markers. In this study, The result of determine rice with WBPH infestation showed that the rice damage and resistance at 7, 14, and 21 days, were 100%, 76%, and 10% resistance lines of 120 CNDH population. Four QTLs were detected on four regions of the chromosomes 1 and chromosome 8, which contained qWBPH1 and qWBPH8 for resistance rice. The markers were found to be contained in identification the genetic markers RM3482, RM1196, RM3709, RM11694, RM11669, RM17699 and RM264 for marker assisted selection. These markers efficiently were shown to be very useful for MAS in breeding populations of crossing lines associated simple sequence repeat (SSR) marker with WBPH resistance in 120 CNDH populations.

The objectives of this study were to investigate the diversity of natural products (DNP7, 9) in responding to Whitebacked planthopper (WBPH) feeding. Resistant rice (cv. Cheongcheong ), susceptible rice (cv. Nagdong) and susceptible control rice (cv. TN1) were used as materials for WBPH infestation in seedling stage. The treatment was conducted by spraying DNP 7 and 9 for 100 ppm to materials before being fed to 2nd and 3rd instar WBPH while control group was not sprayed DNP 7 and 9. The density of WBPH was 7 insect per plant. As a result, WBPH survival rate of 57% was found in the DNP 7 treatment, whereas those in DNP 9 and control were 27% and 71%, respectively. Resistance score of Cheongcheong, Nagdong, and TN1 in DNP 7 treatment were 3.4±0.8, 5.9±1.9, and 6.8±1.6, respectively, while those in DNP 9 treatment were 1.6±0.8, 4.7±1.6, and 7.9 ±1.4, respectively. The plant heights of Cheongcheong, Nagdong, and TN1 in DNP 7 treatment after 3 week infestation were 19.7±3.0, 23.4±7.5, and 15.8±8, respectively while those in DNP 9 treatment were 32.4±4, 26.3±12.7, and 25.9±8.5, respectively. Moreover, chlorophyll content was examined 3 week post infestation. In both DNP 7 and DNP 9 treatment, the chlorophyll levels of Cheongcheong and Nagdong in were higher than that in control. Based on observation and bio-scoring, plant with DNP 9 was strongly resistant to WBPH feeding and the survival rate of WHPB was lower than plant with DNP7.

This experiment conducted to identify the changes of the response when white-back planthopper (WBPH, Sogatella furcifera), were inoculated in 10 days rice leaves after germination. We confirmed the difference between inoculated and uninfected plants by in the different time period (1day, 1 week, 2 weeks, and 3 weeks after inoculation). Breeding rice and WBPH maintained at 26∼28℃ with 60 % humidity. 3 leaves plants (TN1, Cheongcheong, and Nagdong) were inoculated with 2∼3 instars WBPH. Harvested rice plant samples were completely dried in dark condition and then samples were completely immersed in a solution of methanol for 3 days under darkness. Dissolving in water and then de-fatted three times with hexane. 100 ppm samples were applied to HPLC, eluting with acetonitrile and 0.1 % acetic acid by C18 (5ph column Agilant) and detected at 254 nm. We confirmed the difference of peak using LC/MS/MS (API-2000). The results showed that three weeks from the day of inoculation was increased at the molecular weight 118.1, 264.2 and 364.2.